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排序方式: 共有782条查询结果,搜索用时 15 毫秒
1.
E. A. Gurieva P. P. Konstantinov L. V. Prokof D. A. Pshenaĭ-Severin M. I. Fedorov Yu. I. Ravich 《Semiconductors》2006,40(7):763-767
The coefficients of thermopower and electrical and thermal conductivity in the PbTe0.8Se0.1 S 0.1 solid solution with electron concentration (4.6–54) × 1018 cm?3 are studied in the range of 85–300 K (and in some cases up to 700 K). The temperature dependences of electrical and thermal conductivity indicate that the low-temperature electron and phonon scattering initiated by the off-center impurity of sulfur exists. The temperature dependences of the electronic and lattice components of thermal conductivity are calculated in the approximation of a parabolic spectrum and electron scattering by acoustic phonons and neutral substitutional impurities. The lattice thermal conductivity is found to have a feature in the form of a shallow minimum in the range of 85–250 K. A similar feature, while not so clearly pronounced, is found to exist also in Pb1?x SnxTe1?x Sex alloys (x≥0.15) with an off-center tin impurity. An analysis of the possible origins of this effect suggests that, at low temperatures, the Lorentz numbers L of the materials under study are smaller than the L0 numbers employed which correspond to the above scattering mechanisms. The cause of the decrease in L is related to electron scattering at two-level systems, a mechanism whose effect grows with increasing electron energy. An analysis of experimental data obtained at high temperatures, as well as on undoped samples with the lowest possible carrier concentrations, yields the values of L for samples with different electron densities. The minimum value L/L0 = 0.75 is obtained for a lightly doped sample at ~130 K. 相似文献
2.
We report a 20 month old female patient with diploid-triploid mixoploidy (46,XX/69,XXX) syndrome with hypothyroidism and precocious puberty. The triploid cell line was only expressed in the fibroblast culture and comprised the majority (95%) of the cells. Chromosome analysis of the fetal blood sample and peripheral blood sample were normal. The patient shows typical features of full triploidy (growth and severe mental retardation, cranial and facial dysmorphism, complete syndactyly of fingers 3/4, partial syndactyly of toes 2/3) and facial but no body asymmetry. At the age of 5 months central hypothyroidism and precocious puberty were diagnosed. Thin pigmented streaks were visible on the wrists and legs of the patient at the age of 16 months. This is the first patient reported so far with 46,XX/69,XXX mixoploidy suffering from hypothyroidism and precocious puberty. 相似文献
3.
A. A. Konstantinov N. V. Kurenkov A. B. Malinin T. E. Sazonova S. V. Sepman 《Atomic Energy》1989,67(3):696-698
Translated from Atomnaya Énergiya, Vol. 67, No. 3, pp. 215–216, September, 1989. 相似文献
4.
A. M. Kozodaev O. V. Shvedov V. N. Konev B. Yu. Sharkov V. V. Vasil'ev E. B. Volkov N. V. Lazarev A. M. Raskopin G. G. Shimchuk P. V. Bogdanov A. I. Kiryushin V. V. Petrunin E. I. Azhnin E. I. Tyurin I. I. Titaev Yu. P. Severgin A. Yu. Konstantinov 《Atomic Energy》2003,94(1):56-60
The purpose and current construction status, at the Institute of Theoretical and Experimental Physics, of an experimental electronuclear setup, combining a pulsed proton linear accelerator (36 MeV, 0.5 mA) and a subcritical blanket thermal-power assembly 100 kW, are discussed. The main equipment is already available or is being built in industry. The setup can be used to investigate the dynamics of the interaction of a linac–driver and a subcritical reactor and problems concerning the accelerator–driver and the target–blanket assembly. The proton beams and neutron fluxes will be used for applied purposes. In the future it will be possible to increase substantially the current and energy of the proton beam. 相似文献
5.
V. A. Mozhzherin V. Ya. Sakulin V. P. Migal’ A. P. Margishvili A. A. Konstantinov 《Refractories and Industrial Ceramics》2008,49(4):245-250
In the OAO Borovich Refractory Combine production has been assimilated for a complete set of refractories for continuous steel
casting, i.e. from a pipe for protecting a stream of metal to a submerged nozzle. In technical and life characteristics the
products correspond to that of world analogs, they provide accident free steel pouring, make it possible to reduce the specific
consumption of refractories per ton of steel, to increase CBCM productivity, to reduce billet scrap, and to reduce steel cost.
Translated from Novye Ogneupory, No. 8, pp. 4–9, August 2008. 相似文献
6.
N. Balchev D. Kovacheva V. Lovchinov K. Konstantinov K. Petrov 《Journal of Superconductivity》1993,6(1):49-54
The preparation conditions, phase composition, and superconducting properties of Bi-Pb-Sr-Ca-Cu oxide materials from different nominal compositions have been investigated. Nearly single-phase samples from Bi2Pb0.4Sr2Ca3Cu4O
y
, as well as from the proposed compositions Bi1.8Pb0.4Sr2Ca3Cu4O
y
and Bi1.8Pb0.4Sr2Ca2.5Cu3.5O
y
were obtained by a solid-state reaction in air. Samples with the third nominal composition showed the best superconducting properties (T
on=111 K and zero resistance atT
0=103 K). A possible mechanism for the 2223 phase formation in the three investigated compositions has been discussed. 相似文献
7.
This report contains the experience of our centre, using the transvaginally guided puncture procedure, to reduce the number of fetuses in a multifetal pregnancy to a lower number. The aim of the procedure was to improve perinatal outcome and/or to meet the personal desires of patients and their families. We surveyed 148 multifetal pregnancy reductions. The fetus or fetuses overlying the internal os was most commonly reduced. The total uncorrected loss of the entire pregnancy was 13.4%. The corrected pregnancy loss was 11%. Of the 63 twins left after the reduction, 33 delivered preterm. Of the 36 singletons, two delivered preterm. Our conclusion was that multifetal pregnancy reduction is a safe procedure for the mother and has an acceptable loss rate of the entire pregnancy. The reduction of a fetus overlying the internal os by the transvaginal puncture procedure seems to yield results at least as good as the transabdominally performed puncture procedures for multifetal pregnancy reduction. 相似文献
8.
K. Konstantinov N. Balchev G. Gyurov I. Stambolova I. Khristova 《Journal of Superconductivity》1993,6(6):381-386
The superconducting properties and the phase and chemical composition of Bi
x
Pb0.3Sb0.1Sr
y
Ca2Cu3Oz (x=1.5, 1.6, and 1.7;y=1.9, 2.0, and 2.1) materials synthesized by one-step and multistep thermal treatments have been investigated. The multistep annealing between 825–875°C promotes the 2223 phase. The change of Bi concentration has little effect on the 2223 phase formation, regardless of the kind of thermal treatment used, but increasing the Sr concentration (y> 2) strongly inhibits this phase. It has also been established that the loss of Pb after synthesis depends on the initial Bi concentration. The loss of Pb decreases when the initial Bi content is lower. 相似文献
9.
10.